Stepping switch



ATT YS.

Jan. 22, 1957 w. D. MouNcE STEPPING SWITCH Filed March 21, 1950 R 0 3 TENC 5 5 ww, mm n ,qv LV1 m. w Z ww Q T liwmlnlml 1 On. JQ m MN l os A\L\\`. 7s I 3 6 2 Zm m0 Wi'. 4 R Y Y B lllllIJ /C I l l IL STEPPINGSWITCH Whitman D. Mounce, Houston, Tex.

Application March 21, 1950, Serial No. 151,028

4 Claims. (Cl. 340-147) (Granted under Title 35, U. S. Code (1952), sec.266) This invention relates generally to switch devices and moreparticularly to a new and improved counter switch of the type adapted toclose an electric circuit after a predetermined number of electricalimpulses have been received thereby.

Heretofore counter or stepper switches of the conventionalelectromagnetic types have been extensively employed in various forms ofordnance devices such, for example, as in submarine mines, land mines,and the like, wherein such `switches are adapted to close a ring circuitin the mine after allowing the passing thereover of a selected number ofships or other such objects suitable for producing in the mine anelectric signal or impulse operative to advance the stepper of theswitch one step in the direction of the mine tiring position for eachsuch electrical signal produced by the mine.

Ordnance devices of the character indicated are frequently subjected tohigh degrees of acceleration shock whereupon it is not uncommon for themovable elements of the stepper switches therein to be prematurelyadvanced in the direction of mine tiring positions thereby to entirelyalter the responsive characteristics of the mine, or in many instancesthe switch becomes so damaged as to render the mine thereafterinoperable.

The device of the present invention provides for a low energycounterswitch that is relatively insensitive to shock and particularlyadapted for use in mine fuzes, or the like, to establish an electricalconnection between the detonator of the mine and a power source, therebyto tire the mine after a predetermined number of electrical signals havebeen applied to the counter mechanism of the switch.

According to the arrangement of the present invention, a plurality ofswitches are arranged to be closed in successive order as fusibleelements individual thereto are ruptured, each switch being arranged toinsert the fusible element of the next succeeding switch into animpulsereceiving, energizing circuit therefor whereby the fusibleelements are ruptured in successive order as a series of electricalimpulses are passed through the energizing circuit. A detonator, orother electroresponsive device, is connected to the last one of theswitches to be operated and to one side of an impulse source connectedin the energizing circuit, and a preselected `one of the remainingswitches is connected to the other side of the impulse source wherebythe circuit is completed to the detonator, or like device, when apredetermined number of impulses, equal to the number of switches thusconnected in series in the circuit, have been received, and thedetonator, or like device is operated by the next succeeding imulse. pIt is an object of the present invention to provide a new and improvedcounterswitch adapted for closing an electric circuit in response to apredetermined number of electrical impulses applied thereto.

A further object is to provide a new and improved counterswitch for amine tiring circuit adapted to establish an electrical connectionbetween the detonator of nited States Patent O the mine and a powersource for tiring the mine after a predetermined number of tiringsignals have been applied to the switch.

A still further object is to provide a counterswitch wherein a circuitis completed through the switch after successive rupturing of a selectednumber of fusible elements for controlling sequential operation of thecircuit closing elements of the switch.

A further object is to provide a counterswitch adapted to close aplurality of contact members of the switch in sequential order inresponse to a preselected number of electrical impulses thereby toultimately complete a ring circuit to the detonator of the mine.

A still further object is to provide a mine ring counterswitch wherein aplurality of circuits are closed through elements fusible in successiveorder in response to a preselected number of electrical impulses appliedto the switch thereby to effect the ultimate completion of a tiringcircuit to the detonator of the mine.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same become better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

Fig. 1 is a plan view of the counterswitch of the present invention;

Fig. 2 is a side view of the switch ment of the fusible elementsthereof;

Fig. 3 is a view in section of the switch as taken along line 3-3 ofFig. 2; and

Fig. 4 is a schematic View of the switch of the present invention asarranged in a mine firing circuit.

Referring now to the drawings and more particularly to Fig. l thereofthe switch generally designated 5 of the present invention is shown ascomprised of a base member 6 formed preferably from insulating materialsuch, for example, as Bakelite and whereupon is secured as by screws 7 aribbed body or chassis member 8, also preferably formed from Bakelite.Clamped or otherwise suitably secured between these base and bodymembers 6 and 8 respectively is a terminal plate 9 having provided inthe forward edge thereof an upwardly extending flange section 10 whereinis formed a plurality of V-shaped notches 11, Fig. 2, the purposethereof becoming more apparent as the description proceeds. Screws 7, bywhich the terminal plate 9 is secured to the undersurface of the chassis8, provides an electrical connection between the plate and a terminalplate 47 clamped as by the `screws 7 to the upper surface of thechassis.

Respectively arranged between ribs 12 of the chassis is a plurality ofterminal pieces 13, Fig. 3, suitably secured to the chassis as by deepdrawn eyelet portions 14 thereof extending downwardly through boresprovided therefor in the chassis to be thereafter flared at their lowerends 15 for gripping in a conventional manner an showing the arrange--inner flange forming the base of a counterbore 16.

Threaded into the respective eyelets 14 is a pair of clamp screws 19 and20 of which the former thereof is eiective to secure to a selected oneof the terminal pieces 13 a connection 40, Fig. l,` forming a part of amine tiring circuit generally designated 22, Fig. 4 and including adetonator unit 25. The clamp screw 20 is so arranged as to secure to theterminal plate 13 a pair of resilient contact elements including acontact plate 26 and spring switch arm 27 both of which include portionsextending laterally outward from the supporting edge of the chassis andwith an angular portion of the contact plate 26 lying across the springswitch arm of the pair of contact elements adjacent thereto.

The spring switch arms `27 are preferably formed from material moreflexible than the contact plates 26 and gradually narrowed at their freeends to terminate ultimately into upwardly extending contact portions 30initially maintained in open circuit position with -respect to the platemembers 26 by fusible elements 31 secured as by soldering to the ends ofthearms and the flange section .of .plate 9.at 32 `and 33 respectively,tFig. 3. The elements ,31, are so arranged as to pass .through suitableopenings 45 provided therefor in the endsof the arms l27 and lie withinthe notches 11 formed inthe outer edge of the flange section 10.0fyplate 9.

The rupturing of a connected fusible kelement 31, vresponsive to apredetermined voltage applied thereto, frees the 'arm 27 retainedthereby allowing the arm to `spring upwardly for contacting theundersurface of the overlying plate member 26 adjacent thereto thereby-to close in this manner an electrical connection through the vnextsucceeding element .31 by way Iof .the next spring switch 4arm incircuit withthe said contactedplate. Withltherupturing of each .elementan electric circuit is stepped through the switch, in the i mannerindicated, to `be `ultimately completed through the detonator unit forfiring the minera'fter .a predetermined number of :electrical impulseshave been applied to themechanism of the switch. It will be apparentfro-m the structure of the switch that the electrical connection 4t) maybe made ywith any one of the fusible elements 31 selectivelywhereby thenumber Yot' electrical impulses required .to complete the circuitlthrough the switch may be controlled.

The mine tiring circuit 22, Fig. 4, which Vmay be of any type suitablefor application with the switch of the present invention, is shown toinclude a battery 35 initially disconnected from the firing circuit byan arming switch 36 adapted to be closed to arm the mine in anyconventional manner as by the removal of an arming pin therefrom in thecase of land mines, or the like, or by hydrostatic pressure in the caseVof underwater ground mines as the mine submerges to a predetermineddepth within a body of water. The firing circuit also includes a tiringcontrol mechanism 46 Iwhich may be of any type lsuitable to close theswitch 39, or .to otherwise complete the firing circuit between .theconductors 20 and 40. For a more complete disclosure of such a mechanismand iiringicircuit reference may be had to the copending application ofW. D. Mounce et al. for Mine Firing Control System, Serial No. 594,133,lfiled May 16, .1945.

The closing of the arming switch 36 is effective to connect in thebattery circuit a condenser 37 arranged in series with a low valueresistor 38 whereupon the condenser is charged gradually to peakpotential over a predetermined period of time selectable by 'the choiceofthe resistance 3S in the condenser circuit.

The condenser 37 is so arranged .with rrespect to the fusible elements31 that asf-the firing switch 39 is closed, a circuit is completedthrough conductors 4t) and 42 to the element 31, whereupon the condenseris discharged through the element to rupture the same thereby allowing.the 'release of the switch arm 27 retained thereby. The freeing of thespring switch arm in this manner allows the arm to engage theundersurface of the next adjacent contact plate 26, as heretoforedescribed, to complete the electrical circuit through .the switch to thenext succeeding element 31. In this manner, the remaining elements 31are ruptured in successive order in response to successive electricalimpulses received from the condenser 37.

With the rupturing of each element the next succeeding element isprevented from fusing for the reason that the condenser 37 is soselected that when fully charged, it has sutlicient potential to rupturevonly one element and further charging of the condenser to a valuesuficient to rupture the next element is prevented until the Vtiringswitch .39 has been opened for a'predetermined period of time, theselection of the resistor 38 controlling the time required.

The detonator is connected vto condenser 37 by way of conductor 42 andthe other side thereof is connected by way of conductor 41 to terminalstrip 17 which is connected as by a screw 19 to the last one of contactplates 26, conductor 41 being secured to strip 17 also as by a terminalscrew 19. Thus, the detonator is connected so as to be fired by the nextsucceeding impulse from the condenser after a sutcient number ofimpulses have been received to fuse the intervening elements 31 andconnect the last contact plate 26 to conductor 4t?.

Obviously many modifications and variations of the present invention arepossible in Ithe -lightof the above teachings. it is therefore to ybeunderstood that within the scope of the appending claims the inventionmay be practiced otherwise than as specifically described.

The invention described .herein may be manufactured and used by or forthe Government of the United 'States of America for governmentalpurposes without the payment of any royalty thereon or therefor.

What isclaimed as .new vand desired Vto be secured by Letters Patent ofthe United States is:

l. A stepping `switch of the character disclosed adapted to close anelectric circuit through the switch to an apparatus to be energizedafter a predetermined number of electrical impulses have been applied to'the switch including, in combination, a plurality of pairs ofelectrically connected contact devices including a fixed contact memberand a flexible contact member, said flexible contact ymember beingarranged for contacting the fixed contact member of .the adjacent .pair4of devices, a conducting terminal plate, an elongated insulating block,said exible Contact Vmernber -being disposed between said block and thefixed contact'member, a plurality of .fusible lelements respectivelyconnected at one of the ends .thereof tosaid -exible contact members andcommonly connected at the other ofthe ends thereof to said members outof contact with the respective fixed contact .membersof each adjacentpair and in a plane transverse to the longitudinal -axis of said block,and circuit means for receiving said impulses and connected to a firstselected one of said flexible contact members for rupturing the fusibleelement connected thereto thereby to release the selected flexiblecontact member for movement into engagement with the xed contact lmemberof the next succeeding contact device whereby said electric'circuit isprogressively advanced through `the switch in response lto each of saidelectrical impulses.

2. A stepping switch of the character disclosed adapted for use ina minefiring circuit and including, in combination, an elongated insulatingsupport, a plurality of flexible contact ymembers transversely arrangedin closely spaced relation along the longitudinal surface of saidsuppoit and secured thereto, each of said members having `one endthereof extending beyond said support and movable vin .a plane normalthereto, a metallic terminal plate arranged -beneath said support andextending throughout the length thereof, a plurality of fusible elementseach connected .at one end thereof to said plate and at the other endrespectively to the movable endsof said flexible contact members tomaintain said members initially deflected in a retracted Vpositionltoward the plate, circuit lmeans for applying electrical impulses insuccession to said switch, the first of said impulses lbeing applied toa selectedone of said elements to rupture the element therebyto releasefor movement a selected flexible contact member, a plurality of fixedcontact members correspending in number to said flexible members andrespectively arranged across -the paths of movement ofthe flexiblemembers for engagement therewith thereby to connect `the next succeedingfusible element for rupture in response to the next succeedingelectrical impulse as the exible members are released in successiveorder, and electroresponsive means connected to a selected 4one of saidixed contact members .and operable vby said impulse when the flexiblemember operatively associated therewith is released.

3. A stepping switch of the character disclosed adapted to close acircuit to an electroresponsive device when a predetermined number ofelectrical impulses have been applied thereto including, in combination,an elongated insulating chassis comprised of a top section and a basesection, a plurality of spring contact members secured in closely spacedrelation along the upper surface of the top section, each of said springmembers having the contact end thereof adapted for exible movement in aplane normal to the longitudinal axis of said chassis, a metallicterminal plate interposed between said top and base sections an-d havingone edge thereof extending from beneath the top section, a plurality offusible elements each connected at one end thereof to the said edge ofthe terminal plate and at the other end respectively to the movable endsof said spring contact members to maintain said contact ends deflectedtoward the base section of said said contact members and in electricalcontact therewith respectively whereby each of the movable ends of saidcontact members when released respectively engages the next succeedingcontact plate, and means connected to the last contact plate forestablishing an electrical connection to said electroresponsive devicewhereby the circuit to the device is closed by the selected springmember and the 'intermediate spring members as the last spring member isreleased.

4. A stepping switch of the character disclosed adapted to close anelectric circuit in response to a predetermined number of electricalimpulses including, in combination, an elongated insulating block havingthereon a plurality of mutually parallel transverse ribs in mutuallyproximate spaced relation, a plurality of xed contact elementsrespectively arranged between said ribs along the surface of saidinsulating block, each of said elements having an angular portionextending beyond the edge of said block, a plurality of exible contactelements interposed between said block and said rigid contact elementsand secured in electrical contact respectively with said xed contactelements to the surface of said block between said ribs, each of saidexible elements having one end adapted for ilexible movement intoelectrical engagement with the angular portion of the next adjacentlixed contact element, a plurality of `fusible elements, a terminalplate arranged on the opposite side of said insulating block and havingthereon a llange running parallel to the longitudinal axis of said blockand -disposed substantially beneath the movable ends of said ilexiblecontact elements, a plurality of notches formed in said flange in spacedalignment with the movable ends of said flexible contact elements andwherein are respectively secured one end of each of said fusibleelements, fusible means for securing the other ends of said fusibleelements respectively to the movable ends of said flexible contactelements thereby to normally bias the flexible elements in the directionof said plate and ldisengaged from the next adjacent xed contactelements, means including a terminal connector arranged on a selectedilexible contact element for applying an electrical impulse to aselected one of said fusible elements whereby the selected fusibleelement is ruptured by the iirst of said impulses to release theflexible contact element connected thereto for engagement with the nextsucceeding xed contact element, and means for connecting said circuit tothe last one of said ixed contact elements whereby the circuit is closedby the released flexible elements in response to said predeterminednumber of said electrical impulses.

References Cited in the tile of this patent UNITED STATES PATENTS500,248 Young et al. June 27, 1893 520,378 Parson May 22, 1894 2,427,901Clark Sept. 23, 1947

